DynamicLink produces double slash in href when default locale is hidden (hideLocale: 'default-locale')

[ZDSJdeJT]

To Reproduce

1. Configure Fumadocs i18n with the core middleware and set hideLocale: 'default-locale' so the default language has no locale segment in the URL (e.g. /docs/page for default, /zh/docs/page for other locales).
2. On a page under the default locale (address bar shows a path without a locale segment, e.g. /docs/something), add a link using the dynamic-link component with an href that includes a dynamic segment such as /[lang]/docs/other-page (import DynamicLink from fumadocs-core/dynamic-link and set href="/[lang]/docs/other-page").
3. Load the page and check the rendered link’s href in the DOM or by hovering/clicking the link.

Current vs. Expected behavior

• Current: The link href is //docs/other-page (double slash). When the default locale is hidden, useParams() does not provide lang, so [lang] is replaced with an empty string, producing a malformed URL.
• Expected: The link should be /docs/other-page (single slash). When the locale segment is omitted for the default language, the path should be normalized so there are no consecutive slashes.

Provide environment information

Operating System:
  Platform: win32
  Version: Windows 11

Binaries:
  Node: 24.13.1
  pnpm: 10.18.3

Which area(s) are affected? (Select all that apply)

Core

Additional context

No response

[fuma-nama]

the fix will be released on next patch, you can also copy the fixed component as a temporary fix.